How they work
The valve sits on the house side of your gas meter. Strong shaking trips a mechanism inside that shuts off the gas. It stays closed until it's reset, and appliance pilot lights then need relighting.
Seismic valve or excess-flow valve?
An excess-flow valve shuts off gas when flow suddenly jumps, such as when a line breaks. A seismic valve shuts off on shaking, even if no line breaks. Some homes have both.
Requirements
Seismic gas shut-off valves sold in California must be certified by the state. Some cities, including Los Angeles, require them in certain situations such as new construction and larger remodels. We'll tell you whether your project needs one.
Questions
What do I do after the valve trips?
If you smell gas, leave the house and call the gas company. If there's no leak, the valve can be reset and the pilot lights relit. Call us if you'd like us to do it.